Autonomous oxygen titration kept ward patients in range far more of the time

Design

Multicentre, unblinded, parallel-group randomised trial (SAVE-O2 AI)

Population

300 hospitalised adults on supplemental oxygen at 4 US hospitals

Primary outcome

Proportion of time with SpO2 90% to 96% over 72 hours

Effect

85% vs 63% (adjusted difference 21 points, 95% CI 18 to 25)

SAVE-O2 was a multicentre, unblinded, randomised trial at four US hospitals. It enrolled 300 adults hospitalised with acute respiratory illness, trauma, burn or acute care surgery who needed supplemental oxygen. For 72 hours they received either a system that titrated oxygen flow to keep saturation in a set range, or usual manual titration by clinicians.

The primary outcome was the proportion of time with saturation of 90% to 96%. It was 85% with autonomous titration and 63% with usual care (adjusted difference 21 percentage points, 95% CI 18 to 25). Time below 88% was lower (2.0% vs 3.6%, difference -1.3 points, -2.0 to -0.5), and time above 96% fell from 29.1% to 9.2%. Results held across prespecified subgroups, including skin pigmentation categories.

The benefit is in time in range, a process measure. The trial did not test whether less time in hyperoxaemia improves survival or length of stay, and the systems are not available in most Indian wards.

• Autonomous titration kept patients in the 90% to 96% range 85% of the time vs 63% with manual adjustment.
• Hyperoxaemia time fell from 29.1% to 9.2%; most of the gain was in avoiding too much oxygen.
• Time below 88% was small in both arms but lower with automation (2.0% vs 3.6%).
• Results were consistent across skin pigmentation groups.
• Clinical outcomes were not reported, so do not expect a mortality effect from this alone.

Why it matters

Even with nurses and doctors adjusting oxygen, patients spend a third of their time outside the target, most of it on too much oxygen.

Don't overread it

The trial measured time in range for 72 hours, not outcomes such as death, organ support or length of stay.

The statistics, in plain English

The 21-point difference is the average gap in share of time spent in the target band. The very narrow interval (18 to 25) reflects many saturation readings per patient, not certainty that fewer deaths will follow. This is a process outcome and shows the device does what it claims.

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